A5038436175- Optical Coatings and Gratings
- Surface Roughness and Optical Measurements
- Photocathodes and Microchannel Plates
- Electron and X-Ray Spectroscopy Techniques
- Calibration and Measurement Techniques
- Adaptive optics and wavefront sensing
- Optical Systems and Laser Technology
- GaN-based semiconductor devices and materials
- Ga2O3 and related materials
- X-ray Spectroscopy and Fluorescence Analysis
- Solar and Space Plasma Dynamics
- Thin-Film Transistor Technologies
- Photonic and Optical Devices
- Atmospheric Ozone and Climate
- Optical Polarization and Ellipsometry
- Ion-surface interactions and analysis
- Stellar, planetary, and galactic studies
- Plasma Diagnostics and Applications
- Advanced X-ray Imaging Techniques
- Silicon and Solar Cell Technologies
- Diamond and Carbon-based Materials Research
- ZnO doping and properties
- Laser-induced spectroscopy and plasma
- Laser Material Processing Techniques
- Advancements in Photolithography Techniques
Consejo Superior de Investigaciones Científicas
2015-2024
Unidades Centrales Científico-Técnicas
2010-2023
Optica
2021-2023
Instituto de Óptica "Daza de Valdés"
2010-2023
Goddard Space Flight Center
1997-2020
University of America
2020
Instituto de Física Fundamental
2001-2011
Universität Hamburg
2010
Lawrence Berkeley National Laboratory
2009-2010
Center for Free-Electron Laser Science
2010
Self-consistent optical constants of SiO2 and Ta2O5 films have been obtained for their relevance in coatings from the near ultraviolet to infrared spectral ranges, where they are transparent a high refractive index contrast. Particular attention has paid wavelengths close shorter than each material cutoff. The far extreme ranges also covered here, few (SiO2) or almost no constant data (Ta2O5) were available these materials. This work is aimed at filling lack self-consistent sets with very...
The optical constants of ion-beam-sputtered SiC films have been measured by ellipsometry in the 190 to 950 nm range. set data has extended both toward shorter and longer wavelengths with literature, along inter- extrapolations, order obtain a self-consistent means Kramers-Krönig analysis. All correspond that were deposited sputtering on nonheated substrates, hence they are expected be amorphous. A bandgap 1.9 eV for was fitted from obtained constants. good global accuracy estimated through...
The extreme ultraviolet (EUV) reflectance of amorphous tetrahedrally coordinated carbon films (ta-C) prepared by filtered cathodic vacuum arc was measured in the 30-188-nm range at near normal incidence.The grown with average ion energies ~70-140-eV significantly larger than a C film energy ~20 eV and deposited sputtering or evaporation.The difference is attributed to large proportion sp 3 atom bonding ta-C film.This high obtained for onto room-temperature substrates.The higher standard...
Various fluorides are materials in nature that extend their transparency range to the shortest wavelengths far ultraviolet (FUV, 100nm<λ<200 nm). These relevant prepare multilayer coatings FUV for demanding applications such as space instrumentation astrophysics, solar physics and atmosphere physics, well free electron lasers, plasma diagnostics, synchrotron radiation, lithography, spectroscopy, etc. Multilayer design requires an optical constant of coating materials. Multilayers optimally...
Mirrors are a subset of optical components essential for the success current and future space missions. Most telescopes programs ranging from earth observation to astrophysics covering whole electromagnetic spectrum x-rays far-infrared based on reflective optics. operate in diverse harsh environments that range low-earth orbit interplanetary orbits deep space. The operational life observatories spans minutes (sounding rockets) decades (large observatories), performance mirrors within mission...
Progress towards far UV (FUV) coatings with enhanced reflectance is invaluable for future space missions, such as LUVOIR.This research starts the procedure developed to enhance MgF 2 -protected Al through depositing on a heated aluminized substrate [Quijada et al., Proc.SPIE 8450, 84502H (2012)] and it establishes optimum deposition temperature of protective film mirrors high ~90% at 121.6 nm.Al films were deposited room protected various temperatures ranging from 350°C.It has been found...
Tauc-Lorentz model is commonly used to describe the dielectric constant of amorphous semiconductors as a function few parameters. However, this not fully analytic and presents other mathematical shortcomings. A modified self-consistent based on integration [E'-(E + ia)]-1 functions using Tauc-Lorentz`s ε2 expression weight presented. This new meets all requirements optical constants. The main difference with TL stands at photon energies close or smaller than bandgap energy. has been...
We have developed new, Mg/SiC multilayer coatings with corrosion barriers which can be used to efficiently and simultaneously reflect extreme ultraviolet (EUV) radiation in single or multiple narrow bands centered at wavelengths the spectral region from 25 80 nm. Corrosion mitigation was attempted through use of Al-Mg Al thin layers. Three different design concepts were deposited by magnetron sputtering reflectance measured near-normal incidence a broad range. Standard multilayers also for...
The optical constants of ion-beam-sputtered B₄C films have been measured by ellipsometry in the 190-950 nm range. set data has extended toward both shorter and longer wavelengths with literature, along interpolations extrapolations, order to obtain a self-consistent means Kramers-Krönig analysis. All correspond that were deposited sputtering on nonheated substrates, hence they are expected be amorphous. bandgap was calculated as fitting parameter Tauc equations for indirect transitions using...
The sounding rocket Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) was launched on September 3rd, 2015, and successfully detected (with a polarization accuracy of 0.1 %) the linear signals (Stokes Q U) that scattering processes were predicted to produce in hydrogen Lyman-alpha line (Lyα; 121.567 nm). Via Hanle effect, this unique data set may provide novel information about magnetic structure energetics upper solar chromosphere. CLASP instrument safely recovered without any damage we...
Imaging at H Ly-α (121.6 nm), among other spectral lines in the short far UV (FUV), is of high interest for astrophysics, solar, and atmosphere physics, since this line ubiquitously present space observations. However, lack efficient narrowband coatings has mostly prevented such Present future observatories like GLIDE IR/O/UV NASA concept, applications, can benefit from development Ly-α. The current state art FUV lacks performance stability that peak wavelengths shorter than ∼135 nm. We...
The optical constants of electron-beam evaporated boron from 6.8 to 900 eV were calculated through transmittance measurements thin films deposited onto carbon-coated microgrids or LiF substrates in ultrahigh-vacuum conditions. In the low-energy part spectrum performed situ on freshly samples, whereas high-energy range samples exposed atmosphere before measurements. extinction coefficient was directly data, and a Kramers-Kronig analysis that combined current data with literature determine...
Multilayer coatings with three layers were designed to yield an increase in normal-incidence reflectance the extreme ultraviolet over that of available single-layer coatings. based on Al, MgF(2), and either SiC or B(4)C demonstrated have higher than single spectral region from 57.9 nm H Lyman-alpha line (121.6 nm) above. The was at wavelengths close 121.6 nm. Reflectance degraded slightly time same way as for layers. After a few months, multilayer maintained their counterparts.
Sub-quarterwave multilayer coatings with more than two different materials are shown to provide a reflectance enhancement compared the standard two-material when is limited by material absorption. A remarkable obtained in moderately absorbing. simple rule based on optical constants provided select most suitable for and arrange correct sequence order obtain highest possible reflectance. It that sub-quarterwave multilayers generalize concept of multilayers, which particular case. Various...
The transmittance and the optical constants of SrF2 thin films, a candidate material for multilayer coatings operating in extreme ultraviolet soft x-rays, have been determined spectral range 25–780 eV, most which no experimental data were previously available. films various thicknesses deposited by evaporation onto room-temperature, Al support their was measured with synchrotron radiation. as function film thickness used to calculate extinction coefficient k at each photon energy. A decrease...
More efficient and stable far ultraviolet (FUV) mirrors will enable future space observatories. Traditional FUV are based on MgF2-protected Al. AlF3 has been identified as a promising substitute for MgF2 to prevent Al oxidation. Hence, the reflectivity, stability, morphology of AlF3-protected have investigated function deposition temperature film. In this work, it is shown how an important parameter whose optimization ultimately yields valuable throughput enhancement improved endurance large...
Reflectance measurements and optical constants of thin films ion-beam-deposited SiC, Mo, Mg(2)Si, InSb evaporated Cr have been measured in the extreme-ultraviolet (EUV) spectral region from 49.0 to 200.0 nm. In this no constant data were available for materials deposited by ion-beam deposition. We compared our with those bulk samples prepared different techniques. The goal research has study candidate multilayer coatings EUV.
The transmittance of thin films Sc deposited by evaporation in ultrahigh vacuum conditions has been investigated the 20-1000 eV spectral range. Transmittance measurements were performed situ on layers that over grids coated with a C support film. used to obtain extinction coefficient at each individual photon energy investigated. These data, along data available literature for rest spectrum, refractive index means Kramers-Krönig analysis. Sum-rule tests indicated an acceptable consistency data.
Ion-beam sputtering (IBS) and evaporation are the two deposition techniques that have been used to deposit coatings of Al protected with MgF2 high reflectance in vacuum ultraviolet down 115 nm. Evaporation deposited (ED) IBS resulted a larger (smaller) below (above) 125 nm than well-known all-evaporated coatings. A similar comparison is obtained when film by instead evaporation. The lower versus ED above because absorption former. Both nonprotected Al, as well MgF2, band loss was peaked at...
Polarimetry is a powerful tool for the interpretation of role coronal plasma in energy transfer processes from inner parts Sun to outer space. One key lines observations H I Lyman α (121.6 nm) among few spectral far ultraviolet (FUV), and hence efficient linear polarizers at this line are demanded. New designs based on (Al/MgF2)n multilayer coatings have been developed obtain smallest possible reflectance parallel plane polarization (Rpar) with simultaneous high perpendicular (Rper). Samples...
We present the science cases and technological discussions that came from workshop entitled "Finding UV-Visible Path Forward" held at NASA GSFC June 25-26, 2015. The material presented outlines compelling can be enabled by a next generation space-based observatory dedicated for UV-visible science, technologies are available to include in design, range of possible alternative launch approaches could also enable some science. recommendations Cosmic Origins Program Analysis Group attendees on...
In this work we report on the extensive characterization of amorphous silicon carbide ($a$-SiC) coatings prepared by physical deposition methods. Our investigation is performed within perspective application $a$-SiC as an optical material for high-precision experiments and, in particular, gravitational wave interferometry. We compare results obtained with two different sputtering systems [a standard radio frequency (rf) magnetron and ion-beam sputtering] to grasp impact setups repeatability...
Multilayer beamsplitter polarizers have been developed for improved solar polarimetry at key spectral lines. The advantage of is that a single device separates s from p polarization; this helps minimize attenuation and enables more compact lighter polarimeter, which important space instruments. Polarizers based on Al/AlF3 multilayers were prepared both C IV (155 nm) Mg II (280 lines, Al/MgF2 H Lyman α line (121.6 nm). designed to mainly reflect (transmit) (p) polarization. Beamsplitter...